1. Field
Embodiments relate to an organic light emitting diode (OLED) display.
2. Description of the Related Art
An organic light emitting diode (OLED) display is a self emissive display device that displays images with organic light emitting diodes. The organic light emitting diode emits light by way of energy generated when excitons, being combinations of electrons and holes, within an organic emission layer fall from an excited state to a ground state. Thus, the OLED display displays an image using the light.
The organic light emitting diode (OLED) display may include a switching thin film transistor, a driving thin film transistor, and a capacitor. A common drain voltage Vdd may be applied to a driving source electrode of the driving thin film transistor. The driving drain electrode may be applied with a common source voltage Vss. A current flowing in the organic light emitting element may be controlled by the magnitude of data voltage Vdata applied to the driving gate electrode through the switching thin film transistor.
In order to emit uniform light from the organic light emitting diode (OLED) display, the common drain voltage Vdd should be applied with uniform voltage. However, as the common drain power line (hereinafter, “a common power line”) applying the common drain voltage (Vdd, hereinafter, “a common voltage”) is elongated, the line resistance may be increased, and thus a voltage drop (IR drop) may be generated.
Therefore, the common voltage may be changed according to a position of the common power line such that the same current may not flow to all driving thin film transistors even though one data voltage is applied. The organic light emitting element in which the light emitting degree is determined according to the current may not emit light of a uniform luminance.
Accordingly, consideration of the voltage drop may be important as a size of the organic light emitting diode (OLED) display is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.